The mental health of older adults has become a critical issue with the rising suicide rate in older adults in South Korea. Various factors related to depression can make heterogeneous impacts in different regions. Yet, such spatial perspectives have been rarely integrated with the mental health studies in South Korea. This study aims to explore 1) how differently each factor of sociodemographic characteristics, social interactions, and health-related behaviors is associated with depression of older adults throughout different regions in South Korea, and 2) how those relationships change across five survey years (2008-2016) for a long term. Spatially local regression and small-multiple map visualization were applied to analyze a longitudinal panel survey dataset named KLoSA, collected in South Korea. It is found that age, marital status, in-person social contact frequency, and perceived physical health are significantly correlated with depression in more regions than other variables. The local regression coefficients and significance vary by region and year.